Method and apparatus for temperature change and control
An apparatus for controlling the temperature of a substrate which includes a substrate table and a thermal assembly arranged in the substrate table and in thermal communication with a thermal surface of the substrate table. The thermal assembly includes a channel that carries a heat-transfer fluid. The apparatus further includes a fluid thermal unit which includes a first fluid unit configured to control the temperature of the heat-transfer fluid to a first temperature, a second fluid unit configured to control the temperature of the heat-transfer fluid to a second temperature, and an outlet flow control unit that is in fluid communication with the channel of the thermal assembly and the first and second fluid units. The outlet flow control unit is configured to supply the channel with a controlled heat transfer fluid, which includes at least one of the heat-transfer fluid having a first temperature, the heat transfer fluid having a second temperature or a combination thereof.
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1. Field of the Invention
This invention relates to an apparatus and a method for controlling the temperature of a substrate. More particularly, this invention relates to an apparatus and a method for performing temperature change and temperature control of a substrate.
2. Description of Related Art
The demand for increasing throughput in semiconductors, displays and other types of substrate manufacturing is never-ending. In the semiconductor technology, for example, due to significant capital and operating expenses, even small improvements in the equipment or in the methods of using the equipment can lead to a significant financial advantage.
Many of the processes in substrate processing involve placing the substrate, such as a semiconductor wafer, on a substrate table of a processing system and processing the substrate. These processes generally include chemical processes, plasma induced processes, and etching and deposition processes, and depend on the temperature of the substrate.
SUMMARY OF THE INVENTIONAccording to an aspect of the invention, there is provided an apparatus for controlling a temperature of a substrate, the substrate having a lower surface and an upper surface on which a substrate processing is performed. In an embodiment of the invention, the apparatus includes a substrate table having a thermal surface supporting the substrate lower surface and a thermal assembly arranged in the substrate table and in thermal communication with the thermal surface. The thermal assembly includes a channel that carries a heat-transfer fluid. The apparatus further includes a fluid thermal unit which includes a first fluid unit constructed and arranged to control the temperature of the heat-transfer fluid to a first temperature, a second fluid unit constructed and arranged to control the temperature of the heat transfer fluid to a second temperature, and an outlet flow control unit that is in fluid communication with the channel of the thermal assembly and the first and second fluid units. In this apparatus, the outlet flow control unit is constructed and arranged to supply the channel with a controlled heat transfer fluid, which includes at least one of the heat-transfer fluid having a first temperature, the heat transfer fluid having a second temperature or a combination thereof.
According to another aspect of the invention, there is provided a distributed temperature control system for controlling a temperature of a plurality of equipment, each of the plurality of equipment having a channel that carries a heat-transfer fluid. In an embodiment of the invention, the system includes a fluid thermal unit constructed and arranged to adjust a temperature of the heat-transfer fluid in each of the plurality of equipment. In this system, the thermal unit includes a first fluid unit constructed and arranged to control the temperature of the heat-transfer fluid to a first temperature, a second fluid unit constructed and arranged to control the temperature of the heat transfer fluid to a second temperature, and an outlet flow control unit that is in fluid communication with the channel of each of the plurality of equipment and the first and second fluid units. The outlet flow control unit of the thermal assembly is constructed and arranged to supply the channel of each of the plurality of equipment with the controlled heat transfer fluid, which includes at least one of the heat-transfer fluid having a first temperature, the heat transfer fluid having a second temperature or a combination thereof.
According to yet another aspect of the invention, there is provided a method of controlling a temperature of a substrate supported by a thermal surface of a substrate table, the substrate table including a fluid thermal assembly in thermal communication with the thermal surface. In an embodiment of the invention, the method includes adjusting a heat-transfer fluid of a first source of heat-transfer fluid to a first temperature and adjusting a heat-transfer fluid of a second source of heat-transfer fluid to a second temperature. The method further includes supplying the fluid thermal assembly with a controlled heat-transfer fluid including the heat-transfer fluid from the first source of heat-transfer fluid or the heat-transfer fluid from the second source of heat-transfer fluid or a combination thereof.
BRIEF DESCRIPTION OF THE DRAWINGSThe above and other features of the present invention will be described in conjunction with the accompanying drawings in which:
In the following description, in order to facilitate a thorough understanding of the invention and for purposes of explanation and not limitation, specific details are set forth, such as a particular geometry of the substrate table and various elements arranged in the substrate table. However, it should be understood that the invention may be practiced in other embodiments that depart from these specific details.
The present invention provides an apparatus and a method for temperature change and temperature control of any type of equipment, including that used for materials processing, such as etching or deposition. More particularly, the apparatus and the method may be used, in an embodiment of the invention, for temperature change and control of the thermal part or upper body of a substrate table on which a substrate is disposed.
Referring now to
In the embodiment of the invention represented in
Referring now to
Substrate processing system 500 includes vacuum chamber 520 in which substrate table 501 is arranged. Similarly to the embodiment shown in
It should be understood that channel 504 that carries the heat-transfer fluid may have different shapes. In an embodiment of the invention, channel 504 has a spiral shape and is designed to thermally cover a substantial area of thermal surface 508. This embodiment of the invention is depicted in
It should also be understood that substrate processing system 500 shown in
During processing of substrate 509, adjustment and control of the temperature of the thermal surface may be achieved via wafer temperature measurement system (or sensor) 525 arranged in chamber 520. In an embodiment of the invention, temperature measurements of substrate 509 are taken by wafer temperature measurement system 525 and input into wafer temperature control system 526. In case the temperature needs to be adjusted, control system 526 commands the fluid thermal unit 503 to adjust the temperature, volume and flow rate of the heat-transfer fluid supplied to channel 504. As can be seen in
As can also be seen in
Referring now to
In this embodiment of the invention, fluid thermal unit 703 includes a first fluid unit 729 (or a first source of heat-transfer fluid) constructed and arranged to control/adjust the temperature of the heat-transfer fluid to a first temperature and a second thermal unit 730 (or a second source of heat-transfer fluid) constructed and arranged to control/adjust the temperature of the heat-transfer fluid to a second temperature. This second temperature may be equal to or different from the first temperature. Fluid thermal unit 703 further includes an outlet flow control unit 731 which is in fluid communication with the channel of the thermal assembly through conduit 707, and with first and second fluid units 729 and 730. In the embodiment of the invention shown in
Referring now to
In an embodiment of the invention, it may be desirable that the heat-transfer fluid include electrically non-conductive liquids such as, for example, Fluorinert™ or Galden™. In that way, the heat-transfer fluid will not be conductive in the presence of the radio-frequency power supplied to the substrate table to generate the plasma.
In an embodiment of the invention, the first fluid unit may be a hot fluid unit 929 while the second fluid unit may be a cold fluid unit 930 or vice versa. In such a configuration, it may be possible to suppress the cooler in the first fluid unit and the heater in the second fluid unit (or vice versa). This embodiment of the invention is schematically represented in
In the embodiment of the invention shown in
It should be understood, however, that the outlet flow control unit 731 and the inlet distribution unit 732 may also be operated in a cooperative relationship. Such a parallel mode of operation is schematically illustrated in
In another embodiment of the invention, the fluid thermal unit is configured such that the amount of heat-transfer fluid in each of the units remains substantially constant. In this configuration, the inlet distribution unit may be omitted. This mode of operation of the fluid thermal unit is illustrated in
The outlet flow control unit represented in the different embodiments of the present invention may include a mixer that is configured to supply the channel with a controlled heat transfer fluid including one of the heat-transfer fluid having a first temperature, the heat transfer fluid having a second temperature or a combination thereof. In this embodiment of the invention, the mixer may include a mixing tank and a mixing device configured to mix the heat-transfer fluid having a first temperature with the heat-transfer fluid having a second temperature. In another embodiment of the invention, the mixer 1231 may include a pump 1237 and a mixing flow chamber 1238 having a mixing flow surface 1239. In this embodiment of the invention, the heat-transfer fluid having a first temperature and the heat-transfer fluid having a second temperature are directed to a chamber similar to the one illustrated in
In another embodiment of the invention, the outlet flow control unit may include selector valves that are configured to selectively send the heat-transfer fluid having the first temperature and the heat-transfer fluid having a second temperature. This embodiment of the invention is represented in
In operation, the inlet and outlet valves may be operated independently from each other or in a cooperative relationship. This latter configuration, illustrated in
Operation of the thermal unit according to an embodiment of the invention will now be explained.
In case the temperature of the controlled heat-transfer fluid lays in the range between T3 and T4, where T3>T4, the first fluid unit of the fluid thermal unit may then set the first temperature to T1≧T3 while the second fluid unit may set the second temperature to T2≦T4. During the initial stage of a heating phase, the outlet flow control unit may be configured to supply the thermal assembly with the heat-transfer fluid having the first temperature T1. This may allow for a faster heating of the substrate. Then, when the temperature of the substrate gets closer to the aimed temperature T3, the outlet flow control unit may be controlled to slowly release the heat-transfer fluid having the second temperature T2 (or a mixture of these two fluids). In such a mode of operation, it may be possible to rapidly change the temperature of the thermal surface while providing at the same time a smooth transition between the actual temperature of the thermal surface and the target temperature.
In the cooling phase, the thermal unit may be operated in a similar manner. That is, the outlet flow control unit may be configured to supply the thermal assembly with the heat-transfer fluid having a second temperature T2 during the initial stage of the cooling process. With this mode of operation, it may be possible to quickly reach the target temperature T4. Then, when the substrate temperature gets closer to the target temperature, the outlet flow control unit of the fluid thermal unit may slowly start supplying the thermal assembly with the heat-transfer fluid having the first temperature T1 (or with a mixture of these fluids). In this way, it may be possible to rapidly change the temperature of the thermal surface while providing at the same time a smooth transition between the actual temperature of the thermal surface and the target temperature.
In order to obtain faster temperature changes, the fluid thermal unit may, in an embodiment of the invention, be configured to overheat and/or overcool the heat-transfer fluid. In this embodiment of the invention, the overheated fluid has a temperature T1>T3, and the overcooled fluid has a temperature T2<T4. The larger the difference is between T1 and T3, the faster heating will occur. Similarly, the larger the difference is between T2 and T4, the faster cooling will occur.
In anticipation of a heating phase, the fluid thermal unit may be configured, in an embodiment of the invention, to store large amounts of heat-transfer fluid in the storage tank of the first fluid unit. The storage of heat-transfer fluid having a first temperature (hot temperature in the present case) would be done at the expense of the storage tank of the second fluid unit. In this embodiment of the invention, a larger amount of hot heat-transfer fluid (i.e. heat-transfer fluid having a first temperature) may be useful to provide faster heating of the substrate, especially when the thermal mass of the substrate table is significant.
A similar approach may be pursued in anticipation of a cooling phase. In that case, the fluid thermal unit may be configured to store a larger amount of heat-transfer fluid in the second fluid unit (that works in cooling mode).
In another embodiment of the invention, the fluid thermal unit may be configured to provide faster heating/cooling by increasing the flow rate of the controlled heat-transfer fluid supplied to the channel. In this mode of operation, a steeper heating or cooling front may be obtained.
It should be understood that the different elements of the fluid thermal unit may be controlled by the temperature control system. This temperature control system may include electronic/computer units that control the different parts of the outlet flow control unit, the inlet distribution unit and the first and second fluid units on the basis of data collected by temperature probes. The temperature control system may also be configured, in an embodiment of the invention, to directly monitor the temperature of the heat-transfer fluid in the first and second thermal units. In another embodiment of the invention, the temperature control system may be configured to read executable instructions of a programmed process scenario (of temperature variation).
Referring now in more detail to
As can be seen in
In the embodiment of the invention shown in
The distributed temperature control system 1600 enables one to efficiently control a temperature of each of these equipment. In operation, the fluid thermal unit 1603 may be coupled to a temperature control system, which may be similar to the one represented in the embodiment of the invention shown in
In an embodiment of the invention, the fluid thermal unit 1603 may be located outside a clean room. In another embodiment of the invention, only the fluid unit acting as the refrigerating unit may be located outside the clean room and/or apart from the other fluid unit. These configurations may be desirable when the type of refrigeration used to cool the heat-transfer fluid and the conditions of the clean room are not compatible.
While a detailed description of presently preferred embodiments of the invention have been given above, various alternatives, modifications, and equivalents will be apparent to those skilled in the art without varying from the spirit of the invention. Therefore, the above description should not be taken as limiting the scope of the invention, which is defined by the appended claims.
Claims
1. An apparatus for controlling a temperature of a substrate, the substrate having a lower surface and an upper surface on which a substrate processing is performed, the apparatus comprising:
- a substrate table having a thermal surface supporting the substrate lower surface;
- a thermal assembly arranged in the substrate table and in thermal communication with the thermal surface, the thermal assembly comprising a channel that carries a heat-transfer fluid; and
- a fluid thermal unit constructed and arranged to adjust a temperature of the heat-transfer fluid, the fluid thermal unit comprising: a first fluid unit constructed and arranged to control the temperature of the heat-transfer fluid to a first temperature; a second fluid unit constructed and arranged to control the temperature of the heat transfer fluid to a second temperature; and an outlet flow control unit that is in fluid communication with the channel of the thermal assembly and the first and second fluid units, the outlet flow control unit being constructed and arranged to supply the channel with a controlled heat transfer fluid comprising at least one of the heat-transfer fluid having a first temperature, the heat transfer fluid having a second temperature or a combination thereof.
2. An apparatus as recited in claim 1, further comprising an inlet distribution unit that is in fluid communication with the channel of the thermal assembly and the first and second fluid units, the inlet distribution unit being constructed and arranged to control a volume, a flow rate, or combination thereof of controlled heat transfer fluid flowing to the first fluid unit and a volume, a flow rate, or combination thereof of controlled heat transfer fluid flowing to the second fluid unit.
3. An apparatus as recited in claim 1, wherein each of the first and second fluid units comprises a storage fluid tank, a pump, a heater and a cooler.
4. An apparatus as recited in claim 1, further comprising a temperature control system constructed and arranged to control a supply of the controlled heat-transfer fluid based upon a temperature of one of the substrate surface, the thermal surface and the controlled heat-transfer fluid in the channel.
5. An apparatus as recited in claim 1, further comprising a temperature sensor constructed and arranged to detect a temperature of one of the thermal surface, the substrate surface and the controlled heat-transfer fluid in the channel.
6. An apparatus as recited in claim 1, wherein each of the first and second fluid units comprises a temperature sensor to detect a temperature of the heat-transfer fluid inside the unit.
7. An apparatus as recited in claim 3, wherein each of the first and second fluid units further comprises a level sensor configured to detect a volume of heat-transfer fluid in the storage fluid tank.
8. An apparatus as recited in claim 2, wherein the outlet flow control unit is in a cooperative relationship with the inlet distribution unit such that a volume of heat-transfer fluid located in each of the first and second units is substantially constant.
9. An apparatus as recited in claim 1, wherein the outlet flow control unit comprises a first valve constructed and arranged to allow the heat-transfer fluid having a first temperature to flow from the first fluid unit and a second valve constructed and arranged to allow the heat-transfer fluid having a second temperature to flow from the second fluid unit.
10. An apparatus as recited in claim 1, wherein the first fluid unit comprises a storage fluid tank and a heater and wherein the second fluid unit comprises a storage fluid tank and a cooler.
11. An apparatus as recited in claim 1, wherein one of the first fluid unit and the second fluid unit is located remotely from the substrate table.
12. An apparatus as recited in claim 1, wherein the thermal surface is located within a vacuum process chamber.
13. An apparatus as recited in claim 12, wherein the vacuum process chamber is a plasma process chamber.
14. An apparatus as recited in claim 1, further comprising an electrode arranged in the substrate table and configured to electrostatically clamp the substrate to the thermal surface of the substrate table.
15. An apparatus as recited in claim 1, further comprising a second thermal assembly in thermal communication with the thermal surface.
16. An apparatus as recited in claim 15, wherein the second thermal assembly comprises a plurality of thermoelectric modules.
17. An apparatus as recited in claim 1, further comprising a gas conduit passing through the substrate table and having a first end open to the thermal surface and a second end opposite the first end such that a gas can flow through said conduit and provide backside pressure to the substrate.
18. An apparatus as recited in claim 1, further comprising an RF power plate arranged in the substrate table and an RF power connector that connects the RF power plate to an RF power supply.
19. An apparatus as recited in claim 1, further comprising at least one pin constructed and arranged to place and remove the substrate on the thermal surface wherein the at least one pin passes through the thermal assembly.
20. An apparatus as recited in claim 1, further comprising mechanical or suction clamps to clamp the substrate.
21. An apparatus as recited in claim 4, wherein the temperature control system is further configured to prevent temperature overshooting during fast heating or fast cooling of the thermal surface.
22. An apparatus as recited in claim 21, wherein during fast heating the temperature of the thermal surface increases quickly and then slowly when the temperature of the thermal surface is substantially close to a desired temperature.
23. An apparatus as recited in claim 21, wherein during fast cooling the temperature of the thermal surface decreases quickly and then slowly when the temperature of the thermal surface is substantially close to a desired temperature.
24. A distributed temperature control system for controlling a temperature of a plurality of equipment, each of the plurality of equipment having a channel that carries a heat-transfer fluid, the system comprising:
- a fluid thermal unit constructed and arranged to adjust a temperature of the heat-transfer fluid for each of the plurality of equipment, the thermal unit comprising: a first fluid unit constructed and arranged to control the temperature of the heat-transfer fluid to a first temperature; a second fluid unit constructed and arranged to control the temperature of the heat transfer fluid to a second temperature; and an outlet flow control unit that is in fluid communication with the channel of each of the plurality of equipment and the first and second fluid units, the outlet flow control unit being constructed and arranged to supply the channel of each of the plurality of equipments with the controlled heat transfer fluid comprising at least one of the heat-transfer fluid having a first temperature, the heat transfer fluid having a second temperature or a combination thereof.
25. A method of controlling a temperature of a substrate supported by a thermal surface of a substrate table, the substrate table including a fluid thermal assembly in thermal communication with the thermal surface, the method comprising:
- adjusting a heat-transfer fluid of a first source of heat-transfer fluid to a first temperature;
- adjusting a heat-transfer fluid of a second source of heat-transfer fluid to a second temperature; and
- supplying the fluid thermal assembly with a controlled heat-transfer fluid comprising the heat-transfer fluid from the first source of heat-transfer fluid or the heat-transfer fluid from the second source of heat-transfer fluid, or a combination thereof.
26. A method as recited in claim 25, wherein during an initial stage of a heating or a cooling phase the supplying comprises supplying the fluid thermal assembly with only the heat-transfer fluid from the first source of heat-transfer fluid or the heat-transfer fluid from the second source of heat-transfer fluid.
27. A method as recited in claim 26, further comprising overheating or overcooling the heat-transfer fluid from the first source of heat-transfer fluid or the heat-transfer fluid from the second source of heat-transfer fluid.
28. A method as recited in claim 25, wherein in anticipation of a heating phase or a cooling phase the method further comprises increasing an amount of heat-transfer fluid in the first source of heat-transfer fluid or the second source of heat-transfer fluid.
29. A method as recited in claim 26, wherein the method further comprises increasing a flow rate of the controlled heat-transfer fluid supplied to the fluid thermal assembly.
30. A method as recited in claim 25, further comprising detecting a temperature of the controlled heat-transfer fluid, the thermal surface or the substrate and controlling the supplying based on the detected temperature.
31. A method as recited in claim 25, further comprising controlling the supplying on the basis of readable instructions of a programmed process scenario.
Type: Application
Filed: Apr 15, 2004
Publication Date: Oct 20, 2005
Applicant: Tokyo Electron Limited (Tokyo)
Inventor: Paul Moroz (Marblehead, MA)
Application Number: 10/824,643